'In a March 7 news release, NASA said its Commercial Crew Program is set to return human spaceflight launches to the International Space Station from U.S. soil in the near future. NASA's critical obligation is to ensure crew safety and success for NASA missions, and the commercial providers are responsible for safe operations of commercial crew transportation systems.

'One of the first requirements for the program included provisions to equip spacecraft with launch escape systems to survive launch and ascent emergencies. From there, each design phase has included ever-more-exacting consideration of safety factors in areas ranging from subsystems, to integrated systems to mission operations.

'Boeing and SpaceX have built simulators and mock-ups that design teams work in and refine with an eye toward safety, as well as practicality and manufacturing. Like previous human spaceflight programs, the astronauts will have extensive training prior to flight, preparing them to fly the spacecraft on launch day. The crews will have rehearsed every scenario possible in the commercial crew vehicles before their first mission.

'Astronauts have been deeply embedded with all of the testing and evaluations throughout, too. They work through regular and contingency scenarios frequently with Boeing and SpaceX designers and engineers.'